1. Field of the Invention
The present invention relates to paper calenders, and more specifically to paper calenders with at least two rolls, one of which having an elastic cover made of plastic and one of which that may be heated by means of a heating device.
2. Discussion of Background Information
Currently, calenders exist that have one or a number of nips, which are defined on the one side, by means of a cast iron roll that can be heated and conducts heat well, and are defined on the other side by means of a roll that has an elastic cover. With the aid of the heating device, a part of the deforming energy is supplied as heat so that in many instances the mechanical deforming energy, which acts as a compressive strain in the nip, can be reduced. In addition, the heat cooperates with the smooth surface of the cast iron roll in such a way that the surface of the paper web is improved with regard to its properties such as brilliance, smoothness, or the like.
German patent DE 27 48 123 A1 discloses dissipating the undesirable heat, which is produced in an elastic cover by means of a flexing work, in such a way that fine metal particles are embedded in the plastic in order to improve the heat conductivity.
German patent DE 195 06 301 A1 discloses a two roll paper calender both one roll supports an elastic cover and the other roll is heated.